A Glover
Transcript of A Glover
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Non Destructive Testing Methods in the Wind Power
Industry
Alison Glover, Tech Apps Specialist, OAZNicholas Bublitz, Product Support Manager Americas, ONDT
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2Outline NDT definition Challenges in the Wind Industry
Issues requiring inspection Ultrasound
Conventional Phased Array
Eddy Current/ECA Other techniques
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3NDT acronyms
NDT - Non Destructive Testing
NDI - Non Destructive Inspection
NDE Non Destructive Examination
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4Non-Destructive Testing What is NDT?
Group of analysis techniques used in science and industry to evaluate the properties of a material, component or system without causing permanent damage or alterations
Cf: Destructive Testing used to evaluate a specimen until or after its failure, eg Crash testing of vehicles Sectioning and micrography
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5Why NDT? Cost effective
parts/equipment without defects not needlessly destroyed
repairs done only where needed (eg welds) Can be done
In manufacturing In service
Data for conditioning monitoring/service planning
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6NDT Challenges in Wind Power Industry 1 Highly visible
Mass production fairly new lack of standards and case histories
Push for large, lighter, more productive units
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7Challenges - 2 Many materials
Metals, composites (eg GRFP), wood
Access from one side only; top of towers
ConfidentialityBlade design is confidential
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8Manufacturing and In-Service Issues 1 Blades
Delaminations, porosity, resin poor areas Thickness Adhesive failure Lightning Strikes
Porosity Delaminations
Composite Layers
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9Manufacturing and In-Service Issues 2 Towers
Welds Lack of fusion Porosity Cracks Inclusions
Raw materials Laminations inclusions
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Manufacturing and In-Service Issues 3 Nacelles/Mechanics
Assembly error Design Flaws Cracks Erosion/pitting
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Remote Visual Inspection Gears, bearings,etc High resolution Still or video capture Highly portable Tool attachments eg
recovery
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Remote Visual Inspection
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What is Ultrasound?
Audible sound and UT are mechanical vibrations
UT is above frequency threshold of human hearing, ~20KHz
Typical NDT frequency range 500 KHz 20 MHz
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Ultrasonics Thickness Testing Many materials metals,
plastics, GFRP, fibreglass Thickness, coating
thickness, corrosion, erosion, delamination
One-side access only Very accurate
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Ultrasonic Flaw Detection 1 Largest application
weld testing Conventional or
Phased Array Manual to fully
automated
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Phased Array BasicsPhased Array Basics
For electronic scans, same angle beam scans along the probe.
For sectorial scans, the Focal Laws are changed to give a range of angles.
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Weldrover on Wind Tower Video
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Advantages of Advanced Techniques PA + TOFD 20 OD tower
welds inspected in 2-3 minutes
Full data recording
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Phased Array on Blades Increased detection Faster scanning than
conventional UT More intuitive displays Data storage
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Phased Array on Blades 2
Manual or encoded
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HRL: tower anchor bolt inspection Corrosion found in
submerged threaded section
Bolt had been in service >12 months
Validated PAUT Can inspection without
removing tower or nuts Uses Olympus Omniscan
& Eclipse Scientific bolt scanner
With thanks to Nick Kriesl, HRL Morwell
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Eddy Currents Defects in the material disturb the circular path of the eddy
currents, changing the magnetic coupling with the probe and causing a variation in the impedance of the coil.
Magnetic Field in the coil
AC Current
Eddy Current
Magnetic Field in the test piece
Flaw
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Eddy Current Conventional or ECA Cracks Corrosion Conductivity
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Other Olympus Techniques: High Speed Video
Motion/impact/stress R&D
X-Ray Fluorescence Positive materials Identification (PMI) Materials sorting Fluid analysis and monitoring
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Other NDT Techniques Liquid Penetrant Magnetic Particle (MP, FMP) Radiography (RT) Acoustic Emission Thermography And others.
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Some Considerations for NDT In house or service provider Training/certification Standards/codes Cost Suitability of methods
access, portability, material, flaw type and size, couplant, down time
No one perfect technique! Safety
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Thank you